Another way to determine
cleaning coefficients, explicitly tuning to a selected range of multipoles, is to minimise
power spectrum residuals [1]}, [2]}. Consider the `cleaned' maps,
\(M^{T_\nu {\rm clean}} = (1 + \alpha ^{T_\nu }_s) M^{T_\nu } - \alpha ^{T_\nu }_s M^{T_{\nu _T}}, \) 
